Back support bracket for butterfly chairs



FIG. 1 is a front perspective view of a back support bracket for butterfly chairs embodying my new design;

FIG. 2 is a right end elevation thereof;

FIG. 3 is a rear elevation thereof;

FIG. 4 is a left end elevation thereof;

FIG. 5 is a front elevation thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof. 

The ornamental design for a back support bracket for butterfly chairs, as shown and described. 